MoFoCo 050 Heads.

[stevepugh]

Hi. I've not recieved a PM at all about Roy's mail address.

However, after reading all this about stepped heads, I went out and took some photos of mine now that I have them.
Is there a way of dating the heads at all? there are some markings on the right hand side saying "1109 790" which I'm guessing 1109 could be a date? , and on the left there is a 1 or a 2 one each head. (Assume this means they come matched pairs? )

Anyway, take a look and please help out in pointing out of mine have the bad step...

[stevepugh]

[Steve Arndt]

Typical mofo. No air flow through the heads. It takes hours of file and drill work to open up the air flow cooling passages through the heads.

[stevepugh]

Typical mofo. No air flow through the heads. It takes hours of file and drill work to open up the air flow cooling passages through the heads.

Which bits do I need to be filing and or drilling?

[Steve Arndt]

Typical mofo. No air flow through the heads. It takes hours of file and drill work to open up the air flow cooling passages through the heads.

Which bits do I need to be filing and or drilling?

Good info here.

http://www.thesamba.com/vw/forum/viewto ... c&start=20

See how light shows through? (and air could also flow through) Head on right is cleaned up for better air flow.

[helowrench]

Hi. I've not recieved a PM at all about Roy's mail address.

That is odd, my sent box shows it went out 11OCT at 12:43pm

Anyway. Sent again.

[stevepugh]

Got it now. Thx.

So does it look like my heads have the dreaded step that was talked about above? I'm not sure what I'm looking for.

[Steve Arndt]

Yes they are stepped. That ~ 3/8" wide circumferential area on the top and bottom of the chamber is the step.

[stevepugh]

Yes they are stepped. That ~ 3/8" wide circumferential area on the top and bottom of the chamber is the step.

Ah I see. So how does this affect my build?
And what do I need to do to resolve it?

[shepherd]

You can either accept the fact that you will be running more deck height than is ideal
(.040 min safety clearance + .050 step)
OR
Machine out the step and try to grind some cc's back into the chamber
OR
Run different heads with no step and a bigger chamber to start with. Then you can cut it down to suit the c/r you want.
Been there, done that. An expensive lesson

[stevepugh]

The mofoco spec says its a 53cc chamber. So if I measure this and it is correct and let's say 53cc gives me the desired Compression Ratio I want, is it an issue that the chamber volume encompasses that step?
Or is the step a massive issue for me? The spec I have is almost identical to the CB Engine builders choice kit and they CC the heads in that kit to 53cc! For a 9.5:1 CR.

[shepherd]

Whether it matters to you depends on what your desired deck height is, and if you are concerned with the effects of running a larger deck height than say, .070
The Mofoco head is 53cc's INCLUDING the space inside the walls of the step. If you machine the step away you will have 43cc's.
The step is .050-.055 tall, and the id is smaller than your piston, so you must run at least .040 negative deck (shim under the cylinder, or copper spacer on top) to avoid having the piston hit the step. This will leave you in the area of .090 space from your piston, to the flat surface of the head (quench pad).
Many builders aim for .040 to .060" clearance, based on the theory that it keeps the fuel/ air compressed into the chamber, where the plug is. More space than that spreads out combustion and makes less power and sometimes more heat. This is all what I have found talking with several builders that I trust, but not my own experience, just my disclaimer. I am shooting for .040 on a build right now, and couldn't get the deck height and compression ratio I wanted using the 050 heads. Hope this helps explain it some

[Piledriver]

... Or have the step bored out to bore size, and set it up for zero deck to the jugs, and use the step as the deck shim.
(NO GASKET) OR flycut flat and put in a .050 copper head gasket or base gasket--- same result.

Put a wider LC cam in it.

The crown of the piston is WAY under bore size, the few thou of cylinder wiggle room should not be an issue.

[stevepugh]

... Or have the step bored out to bore size, and set it up for zero deck to the jugs, and use the step as the deck shim.
(NO GASKET) OR flycut flat and put in a .050 copper head gasket or base gasket--- same result.

Put a wider LC cam in it.

The crown of the piston is WAY under bore size, the few thou of cylinder wiggle room should not be an issue.

What can would you put in it?
Wider LC? I had spec'd an fk8. Or fk10.

[Piledriver]

Try https://www.uempistons.com/index.php?ma ... 525fa02016 using the specs from your engine and the various cams, shoot for a DCR between 7 and 7.5 is you intend to run pump gas. (at ~7 you might be able to run regular with a ~1mm deck)

Sounds silly but be sure to follow the instructions about adding 15 degrees to compensate for the cam ramps.